maybe, currently only the neocdz works anyway, so as long as the universe bios is meant to work with that there's a decent chance of it working. I think the original neocd has slightly different hardware, or at least the command sequences it sent didn't seem to make much sense. the code is a mess tho, from the manuals / datasheets I had I couldn't work out which bits were handled by which chip so getting it all shared with the SegaCD (which was meant to be the same controller, but apparently used in a very different way) ended up with some very ugly code that I found no clean way to pull apart into the proper components. The initial code was provided by an FBA dev too, then modified for SegaCD, then modified back for NeoCD which probably didn't help ;-)

for the arcade the unibios ended up supported because a lot of arcade shops were selling it preinstalled. that's less the case for the NeoCD unit, but since MAME is more open to these things these days I think there's a good chance of it being added as an option anyway.

I'd have done it myself, but I'm not active at the moment. Guess you'll have to hope somebody notices and picks it up. A comprehensive list and links to all the different revisions of the NeoCD Uni Bios would help as MAME would likely want to document every release.